Flow cytometers used in medicine and biology have therein incorporated a fluorescence detecting device for identifying the kind of analyte by irradiating the analyte with laser beam and receiving the fluorescence emitted from the fluorochrome of the analyte.
Specifically, flow cytometers use a fluorescent reagent to label a suspension containing an analyte, which is a biological material such as cells, DNA, RNA, enzymes, proteins, etc., in a buffer solution and allows the analyte to flow in a sheath fluid that flows at a speed of about 10 m/s under pressure to produce a laminar sheath flow. The analyte in the flow is irradiated with laser beam, and a fluorescence emitted from the fluorochrome in the biological material is received and used as a label for identifying the biological material.
Flow cytometers can measure intracellular relative amounts of the DNA, RNA, enzymes, proteins, etc. in the cell and quickly analyze their functions. Flow cytometers also use a cell sorter or the like for identifying specific types of cells and chromosomes using a fluorescence to quickly sort and collect only the identified cells and chromosomes alive.
Flow cytometers are required to quickly identify more analytes from fluorescence information in such applications.
Patent Document 1 below describes a fluorescence detecting device. That fluorescence detecting device time-modulates the intensity of laser beam emitted from a laser light source unit and irradiates a biological material, etc. with that laser beam. The fluorescence emitted from the sample is received, and its phase difference information with respect to the modulation signal for the laser beam is used to calculate the fluorescence relaxation time constant of the fluorescence emitted from the biological material, and the like. This supposedly permits identification of many kinds of fluorescences, especially quick and efficient identification of fluorescence signals.